1. Field of the Invention
The invention relates to methods and apparatus for identification of physical characteristics of a human being or other animal. More specifically, the invention relates to the recognition of the physical characteristics of the eyes.
2. Description of the Prior Art
Several known techniques are traditionally used to identify a human being from physical characteristics. Fingerprints are one of the best known because of their extensive use by law enforcement agencies. Identification by fingerprint is especially helpful where an individual has left his fingerprint during the commission of a crime, but in general, the technology of fingerprint identification relies heavily on human judgment. In addition, the collection and detection of fingerprints is typically difficult.
More recently, U.S. Pat. No. 4,109,237 has disclosed an identification technique making use of the retinal vasculature patterns of the human eye. Among the advantages of this technique are that it can be automated, and is simpler than detecting, collecting, and identifying fingerprints. Furthermore, although some individuals may attempt to alter their fingerprints in order to avoid identification, altering the retinal vasculature pattern would be difficult and dangerous, and might impair or destroy the vision in that eye.
It would be advantageous to have an identification technique making use of the unique characteristics of the eye but not requiring pupil dilation and the complex alignment procedure of retinal identification, including focusing on the retina and maintaining alignment with the direction of gaze of the subject. It would also be advantageous to have such an identification technique which could be used with minimal cooperation of the subject.